Ier tunnel kilns



1,623,779 Aprll 5, 1927' E. CRAWFORD KILN FOR GLASS MELTING AND LIKE PURPOSES Filed Oct. 19, 1923 2 Sheets-Sheet 1 u\ I ztt Ig/IIIIIIIIf/Ill INVENTOR fav 5 51% a BY M u A 5/ ATTORNEY ril 5 1927.. A 2 G. E. CRAWFORD mm FOR sLAss MEL-TING AND LIKE PURPOSES i e 19, 1923 2 Sheets-Sheet 2 INVENTOR- ATTORNEY Fatented Apr. 5, 19327.

UNETEE PATENT @FFEQE.

GEORGE E. CRAWFORD, 0F TRENTON, NEW JERSEY, ASSIGNOR TO AMERICAN DRESS- LER TUNNEL V KILNS, INCL, OF CLEVELAND, 03-110, A CORPORATION OF NEW YORK.

KILN FOR GLASS MELTING- JND LIKE PURPOSES.

Application filed Getobcr 19, 1923. Serial No. 669,565.

My present invention relates to tunnel rilns such as continuous and semhcontinuous kilns in which the material to be treated is moved'into and out of the kiln chamber on a movable hearth formed usually by cars or trucks having refractory tops. The invention comprises improvements especially de with particularity in the claims annexed to and forming a part of this specification. For a. better understanding of the invention, however, and the advantages possessed by it reference should be had to the accompaying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings Fig. 1 is a somewhat diagrammatic longitudinal sectional elevation of a kiln;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1;

Fig. 3 is a sectional elevation taken similarly to Fig. 1 and on a larger scale and showing a portion only of the apparatus shown in Fig. 1; and

Fig. 4 is a plan view of a portion of the kiln with the side walls thereof shown in section.

In the drawings I have illustrated the use of my invention in connection with a tunnel kiln in which the kiln chamber A is heated by, internal combustion chambers D arranged on benches A at the opposite sides of the pathway for the goods which are moved through the kiln from one end to the other on the usual movable hearth formed by trucks or cars C running on track rails B. A represents a door at the entrance end of the kiln chamber and A the double doors at the exit end. [is shown each combustion chamber is provided with a, plurality of burner inlets D distributed along a portion of the combustion chamber adjacent the can: end of the kiln. The end the entrance end of the kiln is connected to a group of pipes E which form extensions of the combustion chamber and are connected at the entrance end of the kiln to a header E. The headers E are connected in turn, as by the duct E to a stack or other draft creating device for drawng products of combustion out of the combustion chambers and through the pipe extensionsE thereof. Gas or other combustible fluid is supplied to the burner inlets D by branches F 2 from a conduit F and supply main F. Air to support the combustion of fuel is supplied to each burner inlet as shown by branches G from an conduit G connected to a main supply duct G. Advantageously, for eficiency in operation and to more readily obtain the high temperatures required, the air supplied by the duct G is highly preheated. The combustion chambers D are shown as formed with open ended circulation channels D in their walls which extend transversely to the length of the combustion chambers and are in communication with the interior of the kiln chamber below and above the combustion chamber interiors; the combustion chambers thus being of the general character set forth in the patent of Conrad Dressler No. 1,170,428.

While I have shown and prefer to employ a continuous tunnel kiln of the Dressler type, my invention is not restricted to use in any special kind of a continuous tunnel kiln and in particular is independent of the manner in which the kiin chamber is heated, but has to do with the means which I shall now describe for taking care of the spillage of molten glass such as occurs in case of the breakage of aglass pot X in its passage through the kiln.

As shown each glass pot X is in the form of an inverted truncated cone open at its upper end and centrally disposed upon the car C by which it is transported, but other forms of open or closed pots or receptacles for the glass may be employed. The cars C are each formed as usual with a somewhat massive refractory platform or body portion C, the sideec ges of which are separated by narrow clearance spaces A from from the benches or other stationary portions of the kiln structure. Preferabl though net necessarily, each car has cial provisions for retaining the pot fragments in case of the breakage of a pot supported thereon. These provisions comprise supporting piers C or projections of refractory material rising from the refractory upper portion C of each car and forming a sort of a cage about the pot X which, in case of a fracture of the latter, will prevent the pot fragments, it of any magnitude, from falling off the car, as illustrated in dotted lines in Fig. 2. The piers C are shaped and disposed to offer a. minimum obstruction to the transfer ofradiant heat from the combustion chambers to the pots X. Advantageously, as shown, the side portions of the upper surface of each car are sloped downwardly, so that molten glass will run naturally to the open joints or clearance spaces A between the sides of the car and the benches A Advantageously also, each car is provided with transverse ribs C at its ends which project above the general top surface ol the car and form barriers restricting the flow of molten glass longitudinally of the kiln from the top of one car to another- To dispose of the molten glass entering the clearance spaces A between the cars C and the benches A in case of a pot failure I provide a conveyor H beneath each clearance space A. Each conveyor H is shown as a belt conveyor of the pan conveyor type which runs lengthwise of the kiln through the high temperature portion of the latter. To provide a chamber or space A for each conveyor H, the corresponding bench A and the adjacent sides of the cars are undercut as shown. Each conveyor is shown as provided with the usual supporting wheels H which runbetween the pulleys K and K at the ends of the conveyors on suitable tracks L secured to the adjacent bench A" and to posts L rising from the door (it the kiln in close proximity to the sides of the cars C. One or both. ends of each conveyor may project beyond the corresponding end ot the kiln, but as shown the conveyors do not extend beyond either end. of the kiln. The pulleys K are located in a comparatively cool portion of the kiln chamber adjacent the entrance door A, and the pulleys K are located closely adjacent the exit end of the kiln chamber; A chamber or well A is formed beneath the pulleys K into which all or nearly all of the glass deposited on the conveyor from time to time is discharged as the conveyor pans are turned upside down in running over the pulleys K. A chamber or well 7 may advantageously be formed under the pulleys K to receive any glass falling out of the inverted pans in their travel along the bottom of the kiln chamberfrom the pulley K and swept by the pans to the exit end of the kiln. The chambers A and A should. be accessible from the exterior of the kiln for the removal, from time to time, of glass accumulating therein. Advantageously as shown the overhanging portions of the benches, and the side edges of the cars terminate in drip ledges A and C, respectively, located at a lower level than the immediate adjacent portions of the benches and cars respectively.

To prevent overheating of the conveyor mechanism, as Well as to cool the understructures of the cars C and track rails, conduits M are provided between the upper and lower turns of the conveyi-vr. The conduits M are connected at their ends into suitable headers M and M and provisions not shown are made for causing water or other cooling fluid to flow through the conduits M. As shown other conduits M which may also be connected to the headers M and M may be located in close proximity to the pathway for the conveyor wheels H. It will be apparent, of course, that the conveyors, themselves, substantially restrict flow of tlie kiln atmosphere from the kiln chamber space above the clearance spaces A into the kiln chamber space beneath these clearance spaces. The conveyor pans may be made of sheet metal, but preferably are made of cast iron. To prevent the adherence to the pans of the molten glass running into them, the

pans may be coated with a suitable material, such as whitewash, and in the drawings I have shown a spray pipe 0 in the chamber A for spraying whitewash against the pans when it is desired to do this.

The general operation of the apparatus disclosed will be apparent to those skilled in the art without further explanation. Each glass pot X is filled with the glass forming material before entering the kiln pastthe door A. As each pot moves through. the kiln it is gradually brought up to the melting ten'iperature and ordinarily the kiln will be operated to maintain a high ten'iperature soaking Zone adjacent the exit end of the kiln. As the glass forming materials begin to melt, they contract in bulk and additional material may ad vantagcously be put in the pots as they approach the exit end of the kiln. For this purpose I provide hoppers Q. opening through valve controlled apertures in the roof of the kiln. By opening the damper controlling the flow out of each of these hoppers when a pot X is beneath it, more or less material may be added tothe pot contents. In case of a fracture of a pot in its passage through the kiln, the pot fragments will be retained by the piers as previously described, andv the molten glass will run off the car into the clearance spaces A and thence onto the conveyors H. The molten glass on contact with relatively cool conveyors is chilled and solidifies and is carried by the conveyors to the chamber A into which most of the glass falls as the Lie pans turn down about the pulleys K. As the adherence to the relatively cool pans is not great, especially if the latter be coated with whitewash as suggested, the repeated turning of the conveyor pans over the pulleys K and K will eventually loosen all or practically all of the glass. In practice, if and when this becomes necessary, a workman in the chamber A may hammer the glass off the conveyor pans.

While my invention was especially devised for use in glass melting it can, of course, be used with kilns employed for other purposes where molten material is carried through the kiln chamber in pots or receptacles which may fracture, or in such manner that spillage may otherwise occur.

While in accordance with the provisions of the statutes 1- have illustrated and de- P scribed the best form of apparatus embodying my invention now known to me, it will be apparent to those skilled in the art that cl'ianges may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

Having now described my invention,what I claim as new and desire to secure by Letters Patent, is: i

1. In a kiln comprising an elongated kiln chamber and a movable hearth separated from a portion of the kiln structure at one side of the hearth by a clearance space, the improvements which consist in a conveyor beneath and running longitudinally of said space and adapted to receive material passing downwardly through said space.

2. In a tunnel kiln comprising an elongated kiln chamber, heating means therefor, and a movable hearth separated from a por tion of the kiln structure at one side of the hearth by a clearance space, the improvement which consists in a conveyor located beneath said clearance space and extending longitudinally of the latter and adapted to carry material passing onto the conveyor through said clearance space out of the high temperature zone of the kiln chamber.

3. In a tunnel kiln, the combination with an elongated kiln chamber having a trackway therethrough and a bench at one side of said trackway, of cars running on said trackway and having their upper portions separated from the bench by a narrow clearance space, said cars and bench being undercut to provide a chamber extending longitudinally of the kiln beneath said clearance space, and a belt conveyor located in the last mentioned chamber.

4-. In a tunnel kiln comprising an elongated kiln chamber and a movable hearth separated from a portion of the kiln structure at the side of the hearth by a clearance space, the improvement which consists in mechanism comprising movable material engaging parts located in the kiln chamber below said space for collecting and removing material passing downwardly through said space.

5. In a tunnel kiln comprising an elongated kiln chamber, heating means therefor, and a movable hearth separated from a portion of the kiln structure at the side of the hearth by a clearance space, the improvement which consists in a conveyor located beneath said clearance space and extending longitudinally of the latter and adapted to carry material passing onto the conveyor through said clearance space out of a high temperature zone of the kiln chamber, and cooling conduits in proximity to said conveyors.

6. In a tunnel kiln the combination with an elongated kiln chamber having a trackway therethrough for cars and a bench at the side of said trackway, of cars running on said trackway and having their upper portions separated from the bench by narrow clearance spaces, and a conveyor located beneath said clearance space and extending longitudinally of the kiln through a high temperature zone thereof and having its discharge end within the kiln, said kiln chamber being formed with a well beneath the discharge end of said conveyor.

7. The combination with a tunnel kiln provided with a trackway of cars running on said trackway and provided each with a platform adapted to support a liquid holding receptacle and with pier-like projections from said platform for retaining the broken sections of a receptacle mounted thereon in case the latter breaks in transit through the kiln.

8. The combination with a tunnel kiln provided with a trackway, of cars running on said trackway and provided each with a platform adapted to support a liquid holding receptacle and with projections at the end of said platform for diverting liquid spillage to the sides of the car.

Signed at city of Trenton, in the county of Mercer and State of New Jersey, this second day of October, A. D. 1923.

GEORGE E. CRAlVFOItD. 

